The present invention relates to a new and distinct cultivar of Barberry plant, botanically known as Berberis thunbergii and hereinafter referred to by the name ‘UCONNBTCP4N’.
The new Barberry plant is a product of a planned breeding program conducted in Storrs, Conn. The new barberry plant originated from Berberis thunbergii ‘Crimson Pygmy’ (synonym Berberis thunbergii ‘Atropurpurea Nana’) through the use of the mitotic inhibitor colchicine to create an autotetraploid form of the plant. Nopaternal plant is involved in the creation of ‘UCONNBTCP4N’. Berberis thunbergii ‘Crimson Pygmy’ is not patented and has been used in the nursery industry since 1942. Briefly, nodal explants of in vitro Berberis thunbergii ‘Crimson Pygmy’ shoot cultures were exposed to 0.1% colchicine for 24 hours in liquid culture media. Nodes were then grown out in tissue culture and shoots were segregated into individual shoots and cultured further. Ploidy of individual shoot cultures was then determined by flow cytometry. Shoots converted to tetraploidy were then multiplied in vitro, rooted in vitro, and acclimated to the greenhouse. Eventually, tetraploid plants were grown outdoors in containers and then in the field. Tetraploidy was confirmed multiple times by flow cytometry when plants were in containers and in the field.
Tetraploid plants were created in late 2004 and early 2005. Tetraploid plants were acclimated to the greenhouse, and then to outdoor container culture in spring and summer of 2005. Tetraploid plants were grown outdoors in containers during 2005, 2006 and 2007. In spring 2008, tetraploid plants were planted in the field for long term evaluation. Diploid Berberis thunbergii ‘Crimson Pygmy’ plants from tissue culture were grown alongside tetraploid plants to serve as control plants. During the growing seasons of 2012, 2013, and 2014, tetraploid plants established in the field were evaluated for fruit production, seed production, seed germination and seedling ploidy in comparison to diploid control plants.
Asexual reproduction of Berberis thunbergii ‘UCONNBTCP4N’ by either micropropagation via tissue culture (since 2006) or by softwood stem cuttings (since 2012) made in late June through early July in a controlled laboratory, greenhouse or container nursery environment has shown that the unique features of this new barberry plant are stable and reproduced true-to-type in successive generations of asexual reproduction.